I could customize you could customize he could customize we could customize you could customize they could customize
V-ing form
I could be customizing you could be customizing he could be customizing we could be customizing you could be customizing they could be customizing
Perfect
I could have customized you could have customized he could have customized we could have customized you could have customized they could have customized
V-ing perfect
I could have been customizing you could have been customizing he could have been customizing we could have been customizing you could have been customizing they could have been customizing
Negation
Simple form
I could not customize you could not customize he could not customize we could not customize you could not customize they could not customize
V-ing form
I could not be customizing you could not be customizing he could not be customizing we could not be customizing you could not be customizing they could not be customizing
Perfect
I could not have customized you could not have customized he could not have customized we could not have customized you could not have customized they could not have customized
V-ing perfect
I could not have been customizing you could not have been customizing he could not have been customizing we could not have been customizing you could not have been customizing they could not have been customizing
Interrogative form
Simple form
could I customize? could you customize? could he customize? could we customize? could you customize? could they customize?
V-ing form
could I be customizing? could you be customizing? could he be customizing? could we be customizing? could you be customizing? could they be customizing?
Perfect
could I have customized? could you have customized? could he have customized? could we have customized? could you have customized? could they have customized?
V-ing perfect
could I have been customizing? could you have been customizing? could he have been customizing? could we have been customizing? could you have been customizing? could they have been customizing?
Interro-negative form
Simple form
could I not customize? could you not customize? could he not customize? could we not customize? could you not customize? could they not customize?
V-ing form
could I not be customizing? could you not be customizing? could he not be customizing? could we not be customizing? could you not be customizing? could they not be customizing?
Perfect
could I not have customized? could you not have customized? could he not have customized? could we not have customized? could you not have customized? could they not have customized?
V-ing perfect
could I not have been customizing? could you not have been customizing? could he not have been customizing? could we not have been customizing? could you not have been customizing? could they not have been customizing?